1. Field of the Invention
The present invention relates to technology for preventing packet proliferation, in instances where so-called multi-device link aggregation is implemented on a network.
2. Description of the Related Art
VPLS (Virtual Private LAN Service) is one technology known to date for joining user networks with other user networks using an MPLS (Multiprotocol Label Switching) network to provide a service protocol (SP) enabling Ethernet frames to be forwarded Multipoint-to-Multipoint.
Link aggregation is a known redundant configuration for networks, and has been standardized in IEEE 802.3ad. Multi-device link aggregation, whereby the aforementioned link aggregation spans multiple devices, has been proposed as a redundant configuration for switches, routers, and other network devices. By implementing such multi-device link aggregation for a number of network devices, in the event that one network device should encounter a problem, the network as a whole will be unaffected.
Such multi-device link aggregation is taught, for example, in U.S. Pat. No. 6,910,149.
FIG. 15 is a block diagram depicting a configuration where multi-device link aggregation has been implemented for two network devices. In FIG. 15, by implementing multi-device link aggregation for the two network devices SW2-1 and SW2-2, the two network devices SW2-1 and SW2-2 are viewed as a single virtual device by another network device SW1 connected to these devices. The two network devices SW2-1 and SW2-2 under multi-device link aggregation exchange control message between themselves, while aggregate circuit messages are exchanged between these two network devices SW2-1 and SW2-2 and the other network device SW1.